I cant remember the exact resolutions, but it takes the original raw data from the sensor
It was 1732 X 974. Canon rezises that a few times, applies some chroma subsampling, applies some bad sharpen and noise reduction algorithms and finally compress it using the H.264 codec.

They really know how to screw up an image

That's why even 0.5 Megapixel RAW videos are looking sharper than Canon's default H.264 videos, although they have
really heavy aliasing.
And it's true that the EOS 600D/Rebel T3i is compatible with SDHC and SDXC cards
but it can't use their write speeds. The SD-controller is limited to 21.3 Megabyte/s write speed. If the 650D and 700D have a write speed limit of ~ 40 Megabyte/s they'll probably be able to record 1280 X 720 (Requires 37 Megabyte/s write speed at 24 frames/second) wich is 2 times the resolution of what the 600D can get! Don't complain about that.
Still, the 50D can record 1590 X 890 at 24 frames/second and has a really lovely look. And it can use the full width of its sensor so you don't get higher crop factors than 1.6. If audio and flipscreen aren't needed, a 50D might be the best option for RAW videos for less than 1000 €. I'm curious to see how well it compares to the BMPCC ...